Energy Flow
Which organism type provides the original source of energy for most ecosystems?
Producers
Which group returns nutrients to the soil?
Decomposers
What do arrows in a food web represent?
Direction of energy flow
What term describes the maximum population an environment can support?
Carrying capacity
Which human activity most directly reduces biodiversity?
Habitat destruction
A food chain shows grass → rabbit → hawk. Which organism receives the least amount of energy?
Hawk
Which process moves carbon from the atmosphere into plants?
Photosynthesis
Which organism would be most affected if producers were removed?
Primary consumers
Which factor would most likely increase carrying capacity?
Increased food availability
How does fertilizer runoff affect aquatic ecosystems?
Causes algal blooms and oxygen depletion
Why does energy decrease as it moves up trophic levels?
Energy is lost as heat during metabolic processes
Which process releases carbon dioxide back into the atmosphere?
Cellular respiration
Why are food webs better models than food chains?
They show multiple feeding relationships
A predator population increases. What happens to the prey population?
It decreases
Which solution best reduces overfishing?
Catch limits and fishing regulations
If producers capture 10,000 energy units, approximately how much energy is available to primary consumers?
About 1,000 units
A decrease in decomposers would most directly affect which cycle?
Carbon and nitrogen cycles
If a keystone predator is removed, what is the most likely outcome?
Population imbalance and reduced ecosystem stability
A population graph levels off after rapid growth. What does this indicate?
The population has reached carrying capacity
Which evidence best supports that pollution harms ecosystems?
A. Stable population sizes
B. Increased species diversity
C. Decline in sensitive species
D. Increased energy flow
C. Decline in sensitive species
Which statement best explains why energy does not cycle in ecosystems?
A. Energy is reused by decomposers
B. Energy is converted to heat and lost
C. Energy moves through biogeochemical cycles
D. Energy increases at higher trophic levels
B. Energy is converted to heat and lost
Which statement best compares energy and matter in ecosystems?
A. Both cycle continuously
B. Energy cycles, matter flows
C. Matter cycles, energy flows
D. Both are lost as heat
C. Matter cycles, energy flows
Which model best shows both energy flow and matter cycling?
A. Energy pyramid
B. Population graph
C. Food web with decomposers
D. Trophic level list
C. Food web with decomposers
Which data best supports that competition affects population size?
A. Constant population over time
B. Sudden extinction
C. Decreased growth when resources are limited
D. Increased energy at higher trophic levels
C. Decreased growth when resources are limited
Which claim is best supported by data showing declining fish populations after pollution increases?
A. Pollution has no effect on ecosystems
B. Human activity can disrupt ecosystem stability
C. Energy flow increases with pollution
D. Decomposers are unaffected
B. Human activity can disrupt ecosystem stability